A computed tomography system comprises a radiation source emitting radiation traversing a subject to be imaged and a detector for generating detection values depending on the radiation having traversed the subject. The detection values are generated, while the radiation source and the subject move relative to each other, for instance, while the radiation source rotates around the subject. The computed tomography system further comprises a reconstruction unit for reconstructing an image based on the generated detection values.
If a contrast agent has been injected into the subject, the distribution of the contrast agent within the subject changes with time. Detection values, which have been generated at different times, relate therefore to different concentrations of the contrast agent within the subject, which can lead to image artifacts in the finally reconstructed image.
US20113/0261441A1 discloses determining an amount of a contrast agent in an image from simulated monochromatic contrast-enhanced images, each obtained at a different energy.